Cutting tool



J. W. LAWSON.

CUTTING TOOL.

APPLICATION FILED SEPT. 16. I920.

1 ,406,265, Patented Feb. 14, 1922.

IN VEN TOR. w fife 144% BY m7; 2 W F \q. 6 ATTORNEY UNITED STATES PATENT OFFICE.

CUTTING TOOL.

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Specification of Letters Patent.

Patented Feb. 14, 1922.

Application filed September 16, 1920. Serial No. 410,615.

To all whom it may concern:

Be it known that I, JAMns W. LAWSON, a citizen of the United States, residing at East'Providence, in the county of Providence and State of Rhode Island, have invented certain new and useful Improve ments in Cutting Tools, of which the following is a specification.

My invention relates to that class of cutting tools which comprise a tool or bit mounted in a tool holder, and used on lathes and other machines of similar type, and is directed more particularly to the bit and its mounting.

Heretofore the sockets or channels for receiving the bit have been of excessive cross sectional dimensions to admit the facile insertion of the bit whose exterior surfaces usually have more or less accretions or foreign particles thereon. The clamping screw has for this reason been ineffective to insure a tight seating of the bit in its channel.

The essential objects of my invention are to overcome the above inefiiciency; to insure a rigid seating of the bit, and to make a transverse shifting of the latter in its seat impossible.

To the above ends essentially my invention consists of such parts and combinations of parts as fall. within the scope of the appended claims.

In the accompanying drawings which form a part of this specification Figures 1 and 2, are a side elevation and a plan view respectively of a cutting tool embodying my invention,

Figure 8, an enlarged partial section of a portion of the same on line 33 of Fig. 2,

Figure a, a perspective view of the bit,

Figure 5, an enlarged section on line 55 of Figure 1, and

Figure 6, a modified form of my inventlon taken on a line corresponding to line 3-3 of Figure 2.

Like reference character's indicate like parts throughout the views.

In the drawings 8 is a tool holder comprising the usual flat shank or shaft portion 9 and head portion 10. The head and shank are provided with an inclined socket or channel 12 extending from an intermediate portion of the front of the head to an opening 13 in the bottom face of the shank, as shown in Fig. 8. The opening 13 may, however, be omitted as shown in Figure with out departing from the spirit of my invention. In detail the channel is bounded by a plane upper face 15, plane parallel lateral faces 16 at right angles to the face 15, and a rounded or partially cylindrical lower face 17, as shown in Figure 5. wherein the bit is omitted.

T he tool or bit, represented in a general way by 19, is oblong in form having one or more cutting faces 20 of any usual or con.- venient form on one end. This tool or bit has a plane upper face 22, and parallel lateral faces 24L disposed at right angles to each other, and a rounded or semi cylindrical bottom face 25.

The transverse dimensions of the bit are such as to permit its admission into the channel 12 as a sliding or running fit, with the portion 25 registering in its seat 17.

The head portion 10' of the holder has a vertically inclined threaded opening 27 entering the channel and disposed at right angles to the latter. In the orifice is the shank 28 of a binding screw 29 having the usual squared head 30. The end of the clamping screw is adapted to engage the face 22 of the bit, and frictionally maintains the latter in any position of longitudinal adjustment in the channel.

It is important that the contacting surfaces of the tool and its socket be such that when the set screw is tightened the tool will be automatically brought to its correct position. so that the tool cannot be shifted during the cutting operation. By giving the bottom of the tool the form shown, with its rounded surface and its opposite sides parallel and the top side at right angles to the said sides, and by making the walls of the socket in which the tool is received of a corresponding shape the tool can normally be made a tighter fit in the socket and when the set screw is tightened, if the tool should be so disposed with relation to the socket that its walls are not exactly co-related, as soon as pressure is applied to the set screw the tool will be caused to rock more or less until it is brought into such co-relation that all possibility of lateral movement of the tool in the socket is absolutely prevented. In other words, the tool is self-centered by the adjustment of the set screw, finding a perfect bearing and that in such shape that all tendency to move laterally is overcome. This automatic seating is made possible by the rounded contacting surfaces of the tool and bottom of the socket.

I claim a 1. In a cutting tool of the character set forth, a holder provided with an inclined channel comprising transversely rectangular upper and lateral portions and a partially cylindrical lower portion, a bit mounted in the channel comprising aplane top face having cutting edges, lateral faces disposed at right angles to the top face, and a partially cylindrical bottom face, said bottom face registering in the partially cylindrical por- Men of the channel, and a clamping screw in the holder adapted to engage the top face of the bit.

2. As a new article of manufacture, a bithaving a transversely convex bottom and a body with substantially parallel lateral faces and an upper face at substantially a right 2L1I1gl to said faces and having a cutting ec ge.

In testimony whereof I have aflixed my signature.

JAMES W. LAWSON. 

